Clip invisible parts of image when drawing in 2D textures and GLSL Modes

This commit avoids draw of invisible parts of image in image editor,
making it faster to re-draw the image.

Especially handy when painting on a high-res image when zoomed-in.

1 files changed, 6 insertions, 1 deletions

diff --git a/source/blender/editors/space_image/image_draw.c b/source/blender/editors/space_image/image_draw.c
index 0ddbb1153c0..aff0a4c3d44 100644
--- a/source/blender/editors/space_image/image_draw.c
+++ b/source/blender/editors/space_image/image_draw.c
@@ -526,7 +526,12 @@ static void draw_image_buffer(const bContext *C, SpaceImage *sima, ARegion *ar,
 		}
 
 		if ((sima->flag & (SI_SHOW_R | SI_SHOW_G | SI_SHOW_B)) == 0) {
-			glaDrawImBuf_glsl_ctx(C, ibuf, x, y, GL_NEAREST);
+			int clip_max_x, clip_max_y;
+			UI_view2d_view_to_region(&ar->v2d,
+			                         ar->v2d.cur.xmax, ar->v2d.cur.ymax,
+			                         &clip_max_x, &clip_max_y);
+			glaDrawImBuf_glsl_ctx_clipping(C, ibuf, x, y, GL_NEAREST,
+			                               0, 0, clip_max_x, clip_max_y);
 		}
 		else {
 			unsigned char *display_buffer;